Temporary form support for building concrete bridges



Oct. 19, 1954 w. J. ITIDWELL, JR 2,692,034

TEMPORARY FORM SUPPORT FOR BUILDING CONCRETE BRIDGES Filed March 30,1951 2 Sheets-Sheet 1 IN VENT OR Mmnn J, fiomru. Jk.

35'; f? BY 2 ATTORNEYS W. J. TIDWELL, JR

TEMPORARY FORM SUPPORT FOR BUILDING CONCRETE BRIDGES Filed March 30,1951 2 Sheets-Sheet 2 /2 Manual 770w! JP.

ATTORNEYS Patented Oct. 19, 1954 Zfithtlii QF FICE TEMPQRARY F QRMSUPPORT FOR BUILDING CGNBRETE BRIDGES William J. 'Iidwell, In,Dcuglasville, Ga.

Application March 30, 1951, Serial N 0. 218,465

2 Claims.

This invention relates to concrete bridges and has particular referenceto temporary form supports employed in the erection of such bridges.

The main object of the present invention is to provide an improvedtemporary form supporting assemblage, especially designed for use inbuilding concrete bridges with the usual integral concrete girders andhaving special provision for adjustably supporting spanning beam membersbetween the bridge piers at the desired grade or level without requiringexpensive temporary piling or the like.

A more specific object of the invention is to provide a temporary formsupport comprising a spanning beam member having short beam extensionssecured to each end in spaced relation to the upper side of the beammember to rest upon the bridge piers and support the beam member in itsadjusted position while the bridge is being built.

Another object of the invention is to provide special supporting beamelements removably secured to the opposite ends of a spanning beammember by means of clamping bolts wtih shims or spacer elementsinterposed therebetween to provide for raising or lowering the spanningbeam to the proper grade or level.

A further object of the invention is to provide an improved spanningbeam assemblage in the form of a truss adapted to be assembled on theJob with the desired camber to make ailowance for deflection due to theweight of the green concrete to be poured.

Other objects and advantages of the invention willappear in thespecification, when considered in connection with the accompanyingdrawings, wherein:

Fig. 1 is a side elevation of a form supporting member embodying theinvention, showing it resting upon bridge piers;

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a vertical sectional view taken on the line 3--3 of Fig. 1;

Fig. 4 is a fragmentary sectional view taken on the line 6-4 of Fig. 5;v

Fig. 5 is a fragmentary sectional view taken on the line 5--5 of Fig. 4;and

Fig. 6 is a fragmentary sectional view taken on the line E-6 of Fig. 4.

In the erection of concrete bridges it has been customary to supporttemporary spanning beams between the piers at the proper grade or levelby means of temporary piling or the like. Then,

the formwork is erected in sections on such beams J 2 and shored up byshims or the like toward the middle of the Spam to compensate fordeflection due to the weight of the green concrete to be poured or castthereon. The present invention provides a prefabricated supportingassemblage for such iormwork having provision for carrying the beams asclear spans between piers without the use or expensive piling and thelike. The idea is to provide temporary form supporting members which canbe set in place by derricks or the like and having means for makingnecessary vertical adjustments of the spanning beam members to providefor the desired grade or level. Also the invention provides simplifiedbeam assemblies which can be removed very easily and re-used forerecting sections of a roadway between successive pairs of piers.Furthermore, the idea is to provide a beam member in the form of a trussadapted to be assembled on the job with the necessary camber in thetruss beam to allow for deflection due to the weight of the greenconcrete to be poured.

Referring particularly to the drawings, the preferred embodiment of asingle form support is shown as being mounted upon successive piers P.In this example, the main supporting beam member is shown as being inthe form of a truss comprising an H-beam to having a lower tension chordH made of two pieces of strap metal and a pair of struts 12. The strapmetal chord members are shown as being welded or other" wise secured tothe ends of the H-beam and overlapped and welded at the lower end of oneof the struts 12. The construction is'such that the chord elements maybe heated to expand them and then welded together at their overlappedends to provide for the desired camber of the beam member Iii uponcooling, and thereby allow for deflection of the beam member, due to theweight of the green concrete to be poured.

In accordance with this invention, the truss is shown as being suspendedand positioned between the top portions of the piers, with the upperflange of the H-beam I0 below the level of the piers to allow for thethickness of the floor boards or flooring of the formwork to besupported thereon. It is necessary to adjust the vertical height of thebeam 56 to suit the grade or level of the roadway to be poured. In manyinstances, the piers are slightly above or below the desired grade,requiring such adjustments.

In accordance with this invention, the truss assemblage is suspended asa clear span by means of short and small beam extensions 3 at theopposite ends of the beam l0 and, conveniently,

in the form of small H-beams. These beam extensions are shown as beingsecured to the end portions of the spanning beam I by means of pairs ofbolts M extending through openings in the upper and lower flanges of thebeam l9 and through openings in cross plate l5 and I 5', as shown inFig. 2. Shims or spacer elements [6 are interposed between the opposedflanges of the beams l0 and i3, as shown in Fig. 1. The spacer elementsare preferably in the form of short pieces of pipe filled with cement orconcrete and held in place between spaced stop members I? welded on theupper flange of the spanning beam II]. In order to provide for verticaladjustment of the spanning beam, shims or spacer elements [6 ofdifferent diameters or thicknesses are provided, so that the beam memberit may be raised or lowered with respect to the upper ends of the piersP to provide for the proper grade or level. Also, the outer ends of thesupporting beam extensions 63 are shown as resting on flat shims l8,which are employed to make minor adjustments in the grade or level ofthe beam ID at its ends.

The clamping bolts M are shown as having long, screw-threaded upper endsextending Well above the cross plates l5 to permit the use of shims orspacer elements of widely different diameters, and also to provide forlowering the beam member l0 and thereby permit the removal of theformwork supported thereon, as well as the entire truss, to be re-used.

Figs. 4, 5 and 6 illustrate the manner of em ploying a plurality of theimproved form supports for erecting a bridge with a concrete roadway Rhaving a plurality of integral concrete girders G. The formwork for suchbridges is usually made in sections which can be installed and removedindependently of each other. In this example, the flooring for thegirder forms is shown as comprising boards B which are preferablyassembled in several separate sections and laid across the upper flangesof the pairs of H-beams l0. Then, the sectional formwork is erected uponthe floor boards in a manner well known in the art, so that the formworkcan be removed after the concrete has set. Incidentally, the floorboards B are shorter at the ends of the beams H) where they span thepairs of beams between the beam extensions l3, and the short floorsections can be inserted and removed, like the other floor boardsections or units on the beams I 0.

While the spanning beam members are illustrated as being in the form ofa truss, it will be understood that ordinary I-beams or H-beams may beemployed, if desired. However, the cambered trusses are preferred,because they can easily be assembled on the job and cambered to makeproper allowance for their deflection, thus avoiding the necessity ofusing shims of various thicknesses between the upper flanges of thespanning beams and the floor boards of the formwork.

Obviously, the invention is not restricted to the particular embodimentthereof herein shown 4 and described, but is capable of variousmodifications and changes within the scope of the appended claims.

What is claimed is:

l. A beam assembly for use in supporting forms in building concretebridges of the type having integral, depending concrete girders in thespan between piers, wherein the form for each girder is supported on apair of beam assemblies, said beam assembly comprising a main i memberin the form of a flangedwebbed structural beam adapted to be suspendedhorizontally between a pair of piers, said main member having an upperflange providing a form supporting surface; a pair of short extensionmembers mounted on said main member, one at each end and extendingbeyond the ends thereof, adapted to rest upon the bridge piers, each ofsaid extension members being in the form of a flanged webbed structuralbeam having a lower flange narrower than said upper flange of said mainmember to provide marginal form supporting ledges on the end portions ofthe upper flange of the main beam member; vertically extending clampingbolts vertically adjustably securing the inner ends of the extensionmembers to the end portions of the main member; and spacing shimspositioned between the upper flange of said main member and the lowerflanges of said extension members to provide for adjusting the level ofthe main member to the proper grade, the construction and arrangementbeing such that when said clamping bolts are loosened said main memberis adapted to be lowered from said extension members to a position belowa cast concrete girder, whereby the support form and the beam assemblymay be removed and reused.

2. A beam assembly as set forth in claim 1, wherein said main beammember is in the form of an H-beam and each of said extension mem hersis in the form of an H-beam having flanges narrower than said main beammember and wherein said vertically extending clamping bolts ReferencesCited in the file of this patent UNITED STATES PATENTS.

Number Name Date 736,718 Grimm Aug. 18, 1903 922,885 Gourlay May 25,190.9

1,233,743 Arndt July 17, 191! 1,415,554 Hatch May 9, 1922 1,467,662 VanAalst Sept. 11, 1923 1,563,118 Tonnelier Nov. 24, 1925 2,386,161 HawesOct. 2, 1945 2,403,853 Fromson July 9, 1946

